Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Trulia (NYSE:TRLA) rose nearly 33% in Thursday's late trading following reports that it's in talks to be acquired by Zillow (NASDAQ:ZG). Shares of Zillow also jumped more than 15% on the news.

So what: According to Bloomberg, "people familiar with the matter" say Zillow could value Trulia at as much as $2 billion, and that a deal could be announced as soon as next week. Curiously, the news arrives a little more than a month after Trulia was reportedly in talks to acquire its own smaller rival, Move, in a deal valued at more than $700 million to help the two companies better compete with Zillow.

Now what: With that in mind, remember that the alleged talks are ongoing, and certainly aren't guaranteed to result in a deal. Considering today's massive jump has increased Trulia's market cap to almost exactly the reported acquisition value, I wouldn't blame Trulia investors for taking profits today and putting them to work elsewhere.

Steve Symington owns shares of Apple. The Motley Fool recommends Apple and Zillow. The Motley Fool owns shares of Apple and Zillow. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.